​Harry Giles, Robert Williams, Tony Bradley and John Collins have a lot in common. All four are prospects who are likely to be taken in the first round of this year's NBA Draft, all play the same position and all will likely fill the same role in the NBA. Williams and Giles are currently thought of as likely lottery picks and Bradley and Collins are borderline first rounders. So what gives?

Harry GilesGiles is the most heralded of the group, having entered Duke as the number one recruit in this year's Freshman class according to most lists. He was known for dominating boys at the high school level who had been given the unfortunate task of trying to match up with fully developed man standing 6'10" and 240 pounds. His power and relentless motor gave him the aura of an unstoppable force on the AAU circuit.

However, despite his reputation, Giles revealed his mortality during his high school career by twice tearing his ACL. He also sat out the beginning of his Freshman year at Duke this year after having arthroscopic surgery on his left knee. Because of the surgery, his career has started out cautiously in a limited role off the bench.

Giles is the least proven college player currently being considered for the lottery across all positions, and the more he plays this year, the more I worry that his standing there is based on reputation instead of merit. The only skill that he seems to be elite at is rebounding, averaging 13.9 boards per 40 minutes. He has not stood out for his shot blocking nor for any of his skills on the offensive end. He's currently shooting 45% from the free throw line and has more than twice as many turnovers than assists thus far, two major red flags for forecasting his offensive potential.

At this point I see more Daniel Orton than Julius Randle in Giles, let alone the all-star future that many marked him as destined for.

Robert WilliamsWilliams exploded onto the NBA's radar after a handful of early breakout performances in the Wooden Legacy tournament at the beginning of the season. Today he's a great rim protector and very good both as a team defender and a rebounder. He's also far from his ceiling as a player, playing with a certain rawness on offense while still showing glimpses of being a major threat as a rim runner with his length, athleticism and aggressiveness around the rim.

One of the most intriguing facets of Williams' potential is that he may still be growing. He came into College Station listed at 6'7" and 200 pounds. He's now on Texas A&M's roster at 6'9" and 237 pounds, and looks even longer than those measurements on the court.

As mentioned, where Williams stands out is anchoring a defense with his shot blocking, averaging 4.1 blocks per 40 minutes. He's also not chasing blocks in favor of handling his defensive assignments, shown by a Defensive Rating that is the lowest on his team by 6.1 points. This type of clear lead in Defensive Rating is always a great sign for a prospect, but is especially impressive for a Freshman. Williams currently looks likely to at least end up as a player in the mold of Clint Capela in the league.

Tony BradleyBradley entered this season rated somewhere in between Giles and Williams in the 2016 prospect rankings, usually landing in the top thirty-five or so on most lists. While Giles came into his Freshman year with his top-of-class hype and Williams with his elite physical gifts, Bradley has flown under the radar this year due to his solid if unspectacular game and limited role at North Carolina.

Despite being relatively unknown nationally at this point, Bradley has the look of a player who'll be a ten year pro in the league. His Offensive Rating is the best on the Tar Heel's roster (excluding players outside their top ten in minutes played) and his Defensive Rating is only 3.7 points behind the team's leader, Senior Kennedy Meeks. Bradley's Net Rating is the best on his team as a Freshman amongst a roster full of talented players who were at the top of their recruiting classes. At the end of the day, isn't how much better does this player make his team all that really matters?

There's certainly a value in having players that play within their limitations, a la Malcolm Brogdon. Bradley doesn't have a consistent outside shot yet, so he only takes shots that he has a good chance of making, and is shooting 56% from the floor as a result. Similarly, one of the reason he has such a good Offensive Rating is because he rarely turns the ball over, averaging only 1.7 per 40 minutes and actually having more assists than turnovers to this point. He's a good rebounder and a decent rim protector, though he doesn't impart the same type of fear that Williams does in his opponents. But that's appropriate for Bradley; look for him put together a quietly successful career like PJ Brown for the team that drafts him.

John CollinsCollins is the oddball here, coming into Wake Forest as an unranked recruit and staying for his Sophomore year. What a weirdo.

When watching Collins play, it's like watching a basketball robot who has been sent from the future to dunk on the world off of pick and rolls. There's a beautiful simplicity to his game - threes are not even considered and passing is an afterthought - but give the ball to Collins within ten feet of the hoop and you will receive points. He's shooting 62% from the field and 73% from the line, and is up to 19.1 points per game in only 25.9 minutes per game. He's a long, lean 6'10" with great athleticism that he uses to go over and around defenders. He also shows nice touch on the few jump shots he does take, although usually they're not from far outside the paint.

Collins also rates second on his team in Offensive Rating and first in Defensive Rating (again excluding players outside their top ten in minutes played), showing a significant positive impact on his team's performance similar to Bradley. Despite his success on the court this year, he's harder than the other prospects in this group to find a role that he fits well in the NBA due to his thinner frame. With that in mind, he would be a great partner next to a Center who has three-point range, so Denver, Indiana, Brooklyn, Memphis and Toronto (if Ibaka re-signs) are all nice potential fits. His solid free throw percentage also gives room for hope that he may be able to eventually extend his range. If so, look out.

tl;drGroup Rankings:1. Robert Williams - Long, athletic shot blocker. Future defensive anchor and rim runner.2. John Collins - Positional tweener, but so productive that a role needs to be found. 3. Tony Bradley - Vet in a 19 year old body. High floor as a prospect. 4. Harry Giles - Overrated. Avoid, especially in first round.